Tag Archives: argument for God from logic

In a previous post I drew a distinction between Objective Moral Values and Subjective Moral Values before giving a couple of illustrations of the importance of the distinction in Christian apologetics. In this follow-up I want to take matters few steps further by deploying the distinction in a version of the moral argument for God.

Consider these two propositions:

There are some objective moral values.

All values are subjective.

Each of these claims has arguments in its favor. (If you worry about the second, bear with me.) The reasons for affirming the first proposition are pretty straightforward. When we reflect on certain moral values that we all recognize, we can see that they hold independently of subjective human factors: personal feelings, opinions, desires, goals, and so forth. Take, for example, the moral value (currently the subject of much public discussion) that sexual harassment is wrong. Suppose that every human on the planet became infected with a disease that brought about a kind of moral insanity, with the consequence that everyone began to think that sexual harassment is good and everyone experienced moral sentiments along those lines. Would sexual harassment cease to be morally wrong? Would that moral value change overnight? (If that example doesn’t persuade you, I’m confident it wouldn’t take me long to identify a moral value that you do take to be objective in the sense I defined.)

Earlier this year I received the following thoughtful question from DG (as I will refer to him) about the argument for God from logic, which I quote in full:

In his essay [in Beyond the Control of God?] Professor Welty points out that in TCR [Theistic Conceptual Realism] “objectivity is secured by there being just one omniscient and necessarily existent person whose thoughts are uniquely identified as AOs.” But how do we get to this one from within the confines of a TCR approach alone? And in “The Lord of Non-Contradiction” you and Professor Welty state: “If the laws of logic are necessarily existent thoughts, they can only be the thoughts of a necessarily existent mind.” Here we go from plural thoughts to a singular mind as we do in the conclusion: “But if there are necessarily existent thoughts, there must be a necessarily existent mind; and if there is a necessarily existent mind, there must be a necessarily existent person.” But why not minds or persons? In note 31, you partially address my concern: “It might be objected that the necessary existence of certain thoughts entails only that, necessarily, some minds exist. Presumably the objector envisages a scenario in which every possible world contains one or more contingent minds, and those minds necessarily produce certain thoughts (among which are the laws of logic). Since those thoughts are produced in every possible world, they enjoy necessary existence.” You then show how this option fails and I agree. But what excludes many necessary beings each of which sustain some necessary truths? This is certainly ontologically extravagant and, as Adams notes in his book on Leibniz (p. 181), perhaps we can simply appeal to Ockham’s Razor to deduce one mind. But he adds, and I agree, that “a more rigorous argument would be desirable”.

At first I thought we could, as Quentin Smith suggests in his essay “The Conceptualist Argument for God’s Existence”, claim that the actual world is an infinite conjunction of all true propositions and that such a proposition, following conceptualism, could only be an accusative of one omniscient mind. But to claim there is such an infinite conjunctive proposition that needs a mind to account for it, given the view that propositions are mental effects, seems to assume there is an infinite mind who is thinking the infinite conjunction. Thus the addition of the actual world in the argument appears to beg the question.

I also considered Leibniz’s argument that without one divine mind we can’t account for how necessary truths “can be combined, any one to any one, because any two propositions can be connected to prove a new one”. But here we also seem to presuppose one mind sustaining the infinite conjunction of necessary truths that we discover in our finite combinations. Pruss, in his discussion of Leibniz’s approach, brings in a possible worlds option by pointing out that “the idea of a possible world will contain the ideas of all other possible worlds since at that world it will be true that they are possible” (Actuality, Possibility, and Worlds, 207). But wouldn’t we need one omniscient mind intending the world ensemble that is supposed to help us infer there is one omniscient mind thinking the ensemble?

I suppose we could appeal to a premise that states it is impossible for there to be a necessarily existing mind different from God. But this doesn’t seem persuasive to me at the moment.

As I understand it, the objection can be boiled down to this. Even granting that we’ve shown that necessary truths (such the laws of logic) presuppose a necessarily existent mind, it doesn’t follow that these truths are grounded in only one such mind. As DG puts it:

But what excludes many necessary beings each of which sustain some necessary truths?

An obvious first move would be to appeal to the principle of parsimony. We should not multiply entities beyond necessity. If necessary truths need to be grounded in a necessarily existent mind, then one such mind will suffice. There’s no explanatory need for further minds. But I also agree that “a more rigorous argument would be desirable,” so what follows is a preliminary sketch of one.

Bill Vallicella recently posted some comments on the paper I co-authored with Greg Welty. He states that he’s very sympathetic to our project, but he finds a weak point in our argument that renders it “rationally acceptable, but not rationally compelling.” Here I respond to his concerns.

Here’s a thoughtful email query I received with the title “Friendly Question about God and Logic”:

Recently, I have been reading about God and abstract objects and came across your article in Phil-Christi with Greg Welty regarding God and logic. I thoroughly enjoyed it and found it both persuasive and useful. In doing further reading on your website I came across a follow up article where you argue that atheism presupposes theism (and so does every other ism) and your argument gets close to an objection to the claim that logic depends on God that I have long wondered about. In the article, in reference to Atheism you argue the following:

(1) God does not exist. [assumption for reductio]
(2) It is true that God does not exist. [from (1)]
(3) There is at least one truth (namely, the truth that there is no God). [from (2)]
(4) If there are truths, they are divine thoughts.
(5) There is at least one divine thought. [from (3) and (4)]
(6) If there are divine thoughts, then God exists.
(7) Therefore, God exists. [from (5) and (6)]

Consider the following reconstruction:

(1*) God does not exist. [assumption for reductio]
(2*) It is true that God does not exist. [from (1*)]
(3*) There is at least one truth (namely, the truth that there is no God). [from (2*)]
(4*) Therefore, truth does not depend on God. [from (1*) and (3*)]

Let me make explicit why I think (1*-4*):

(5*) The laws of logic are divine thoughts.
(6*) According to the aseity-sovereignty doctrine if God did not exist then nothing would exist.
(7*) If God did not exist there would be no divine thoughts.
(8*) Therefore, there would be no laws of logic.

But if (5*-8*) hold, the proposition either God exists or He does not, would be a truthful description of that state of affairs and be an instance of the LEM. Likewise, the proposition God exists, would be false, not true. Not both true and false, thus an instance of the LNC.

Or another way of stating it would be:

If God did not exist then nothing would exist. But it seems that even if God did not exist there would be at least one thing that would exist, the state of affairs, nothing exists. Doesn’t that imply/entail that there is at least one truth about that state of affairs, the truth nothing exists? If that is the case don’t we have laws of logic?

I assume my objection is misguided in some way. If you have time to address this question and clarify my error I would appreciate it.

In an article co-authored with Greg Welty I argued that if there are laws of logic then there must be a God. A key part of the argument is to explain why propositions should be understood as divine thoughts.

In a comment on my answer Jeff cited (without necessarily endorsing) some remarks to the contrary by Nate Shannon and William Lane Craig. Another commenter, Ray, also mentioned some relevant footnotes in Scott Oliphint’s God With Us.

In this week’s exciting episode, I examine the arguments of Shannon, Oliphint, and Craig. Do they show that God doesn’t think propositionally or that propositions couldn’t be divine thoughts? Does the doctrine of divine simplicity rule out Theistic Conceptual Realism? Should anyone care either way? We’ll be right back with some answers after the following short section break!Continue reading →

I was wondering though how you might respond to the view held by some in the Reformed camp such as Oliphint (I think at least, so don’t hold me to it) and Poythress that God does not think propositionally. I am not sure if they would advocate the contingency of propositions, then, but if you ever have the time, could you explain how the argument might still go through, or if the objection has no effect at all?

It depends on what exactly is meant by “thinking propositionally”. If the claim is that God’s thoughts aren’t dependent on propositions (conceived as truth-bearing abstract entities) that exist externally to God and independently of God, in some kind of self-existent Platonic realm, then I wholeheartedly agree. Welty and I have argued that propositions are divine thoughts, which would rule out that Platonist scenario.

However, if the claim is that God does not think in terms of propositions at all, then I strongly disagree. For that amounts to saying that God does not think in terms of truth and falsity. Propositions are conventionally defined as the primary truth-bearers (see, e.g., the recently revised SEP entry). Propositions are simply those entities that are non-derivatively true or false. If God has any true thoughts then it follows by the very definition of ‘proposition’ that God thinks propositionally. And, of course, God does have true thoughts. (How could God reveal truths to us without first having true thoughts?)

A correspondent asked me if I could address an objection he had encountered to the argument for God from logic. Here’s the objection as he quoted it, with my comments interspersed:

The authors equivocate when they make the leap to claim that the laws of logic are thoughts. The propositions themselves are certainly thoughts, but how can the truths that the propositions bear be thoughts?

I’m pleased that the objector concedes that “propositions … are certainly thoughts” because that’s a crucial step in the argument! However, the latter part of the question reflects a confusion. In our paper, we adopted the conventional definition of propositions as primary truth-bearers. But this doesn’t mean that propositions bear truths (as though truths were something other than propositions). Rather, it means that propositions are things that can bear the property of truth; they’re things that can be true. Given this definition, truths just are propositions; specifically, they are true propositions.

By this rejection of God, agnosticism has embraced complete relativism. Yet this relativism must furnish a basis for the rejection of the absolute. Accordingly, the standard of self-contradiction taken for granted by antitheistic thought presupposes the absolute for its operation. Antitheism presupposes theism. One must stand upon the solid ground of theism to be an effective antitheist.

“Antitheism presupposes theism” is one of Van Til’s best lines, because it captures in a nutshell the genius of presuppositional apologetics. It’s not merely that theism is true; it’s not merely that theism can be shown to be true; it’s that theism can be shown to be true by any attempt to prove it false. One can prove theism to be false only if, as a matter of fundamental metaphysical fact, theism is true — which is just to say that antitheism is self-defeating.

Philosophia Christi has kindly permitted me to post on my website a preprint of “The Lord of Non-Contradiction: An Argument for God from Logic”, which I co-authored with Greg Welty. I wrote the first version of the paper, but Greg did all the heavy lifting; the argument is indebted to the ideas he developed in his DPhil dissertation on theistic conceptual realism.

Here’s the abstract:

In this paper we offer a new argument for the existence of God. We contend that the laws of logic are metaphysically dependent on the existence of God, understood as a necessarily existent, personal, spiritual being; thus anyone who grants that there are laws of logic should also accept that there is a God. We argue that if our most natural intuitions about them are correct, and if they’re to play the role in our intellectual activities that we take them to play, then the laws of logic are best construed as necessarily existent thoughts — more specifically, as divine thoughts about divine thoughts. We conclude by highlighting some implications for both theistic arguments and antitheistic arguments.

While we don’t discuss Van Til or presuppositional apologetics in the paper, those so inclined will recognize this as a more robust exposition of a common presuppositionalist argument and they’ll also appreciate (I hope) the concluding remarks.